The present disclosure relates to semiconductor structures and methods of forming the same. More particularly, the present disclosure relates to semiconductor based field effect transistors (FETs) which can be used as biosensors and methods of forming the same.
A biomolecule is any molecule that is produced by a living organism, including large macromolecules such as proteins, polysaccharides, lipids, and nucleic acids, as well as small molecules such as primary metabolites, secondary metabolites, and natural products. Detection of biomolecules such as, for example, proteins and viruses play an important role in healthcare and drug discovery.
Traditionally, biomolecules are detected using florescene or isotope labeling and patch clamp. These traditional biomolecule detection methods have limited sensitivity and automation. Also, the traditional biomolecule detection methods exhibit slow response time and require large amounts of reagent, which may not always be available.
Recently, field effect transistor (FET) sensors have been proposed for biosensing. Most FET based sensors are planar and provide improved biosensing capabilities over their traditionally used biomolecule detection methods. In a typical planar FET based sensor, the sensor is used for sensing charged molecules or ions, which cause a change in the drain current of the planar FET sensor when the charged species are brought into proximity with the channel region of the FET sensor.
Despite providing improved biosensing capability over the traditional biomolecule detection methods mentioned above, there is a need for further improvements within FET based sensors. In particular, there is a need for providing FET based sensors which have a high sensing area to volume ratio, while maintaining the density of traditional FET devices.